The present invention relates to a bidirectional insulated DC-DC converter.
In a bidirectional insulated DC-DC converter, electric power is transferred from a secondary side to a primary side of a transformer. For example, in precharge operation, the bidirectional insulated DC-DC converter controls two switching elements which are provided in a secondary circuit connected to the secondary winding of the transformer to perform synchronous rectification for transferring electric power.
Japanese Patent Application Publication No. 2015-228788 discloses such a bidirectional insulated DC-DC converter.
There are provided switching elements for synchronous rectification in the secondary circuit for a transformer of the bidirectional insulated DC-DC converter. When electric power is transferred from the secondary side to the primary side of the transformer, the switching elements are controlled to be turned ON (closed) and OFF (opened). Depending on the duty of the switching elements, no electric power may be transferred during a period of a cycle time, which reduces the efficiency of transferring of electric power from the secondary side to the primary side of the transformer.
The present invention which has been made in light of the problems mentioned above is directed to providing a bidirectional insulated DC-DC converter that reduces the period during which no electric power is transferred for a cycle time during transferring of electric power from a secondary side to a primary side of a transformer.